Naphthoic acid ester plasticizers and method of making

ABSTRACT

Provided are compounds and processes of making and using such compounds of the formula: 
     
       
         
         
             
             
         
       
         
         
           
             Wherein R=C4 to C15 linear or branched alkyls 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
             wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol. Such compounds provide advantageous properties when used as plasticizers in polymer compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/438,495, filed on Dec. 23, 2016, the entire contents of which are incorporated herein by reference.

This application also claims the benefit of U.S. Provisional Application No. 62/416,944, filed on Nov. 3, 2016, the entire contents of which are incorporated herein by reference.

FIELD

This disclosure is related to a potential route to aromatic OXO-ester plasticizers. More particularly it relates to naphthoic acid ester plasticizers, their use in polymer compositions and methods of making therein.

BACKGROUND

Plasticizers are incorporated into a resin (usually a plastic or elastomer) to increase the flexibility, workability, or dispensability of the resin. The largest use of plasticizers is in the production of “plasticized” or flexible polyvinyl chloride (PVC) products. Typical uses of plasticized PVC include films, sheets, tubing, coated fabrics, wire and cable insulation and jacketing, toys, flooring materials such as vinyl sheet flooring or vinyl floor tiles, adhesives, sealants, inks, and medical products such as blood bags and tubing, and the like.

Other polymer systems that use small amounts of plasticizers include polyvinyl butyral, acrylic polymers, nylon, polyolefins, polyurethanes, and certain fluoroplastics. Plasticizers can also be used with rubber (although often these materials fall under the definition of extenders for rubber rather than plasticizers). A listing of the major plasticizers and their compatibilities with different polymer systems is provided in “Plasticizers,” A. D. Godwin, in Applied Polymer Science 21st Century, edited by C. D. Craver and C. E. Carraher, Elsevier (2000); pp. 157-175.

Plasticizers can be characterized on the basis of their chemical structure. The most important chemical class of plasticizers is phthalic acid esters, which accounted for 85% worldwide of PVC plasticizer usage in 2002. However, in the recent past there has been an effort to decrease the use of low molecular weight phthalate esters as plasticizers in PVC, particularly in end uses where the product contacts food, such as bottle cap liners and sealants, medical and food films, or for medical examination gloves, blood bags, and IV delivery systems, flexible tubing, or for toys, and the like. For these and most other uses of plasticized polymer systems, however, a successful substitute for phthalate esters has heretofore not materialized.

One such suggested alternative to phthalates are esters based on cyclohexanoic acid. In the late 1990's and early 2000's, various compositions based on cyclohexanoate, cyclohexanedioates, and cyclohexanepolyoate esters were said to be useful for a range of goods from semi-rigid to highly flexible materials. See, for instance, WO 99/32427, WO 2004/046078, WO 2003/029339, WO 2004/046078, U.S. Application No. 2006-0247461, and U.S. Pat. No. 7,297,738.

Other suggested alternatives include esters based on benzoic acid (see, for instance, U.S. Pat. No. 6,740,254 and U.S. Provisional Patent Application No. 61/040,480, filed Mar. 28, 2008 and polyketones, such as described in U.S. Pat. No. 6,777,514 and U.S. Pat. No. 8,115,034. Epoxidized soybean oil, which has much longer alkyl groups (C₁₆ to C₁₈) has been tried as a plasticizer, but is generally used as a PVC stabilizer. Stabilizers are used in much lower concentrations than plasticizers. U.S. Provisional Patent Application No. 61/203,626, filed Dec. 24, 2008, discloses triglycerides with a total carbon number of the triester groups between 20 and 25, produced by esterification of glycerol with a combination of acids derived from the hydroformylation and subsequent oxidation of C₃ to C₉ olefins, having excellent compatibility with a wide variety of resins and that can be made with a high throughput.

U.S. Pat. No. 3,284,220 to Anagnostopoulos et al. discloses substituted phenyl ethers of certain mono- and polycarboxylic naphthoic acids and their use as stabilizers for polymeric substances.

U.S. Pat. No. 5,095,135 to Yamada et al. discloses a process for the preparation of naphthalene carboxylic acid esters in which a substituted naphthalene is oxidized with molecular oxygen in the presence of a heavy metal-based catalyst in a solvent comprising a lower aliphatic monocarboxylic acid to form a naphthalene carboxylic acid and the resulting acid is then esterified. The esterified product is purified by washing, recrystallization, and distillation in that order. Heavy metals are recovered as carbonates from filtrates and washings obtained by separation of crude acid and ester products and by washing thereof.

U.S. Patent Publication No. 2014/0179845, herein incorporated by reference in its entirely, discloses compounds and processes of making compounds of the formula:

wherein x=4 to 8, R is H, C₁ to C₄ alkyl, —C(O)OR₁ or —OC(O)R₁, y=4 to 8, R′ is H, C₁ to C₄ alkyl, and at least one R′ is —C(O)OR₁ or —OC(O)R₁, wherein R₁ is a branched C₄ to C₁₄ alkyl, and their use in polymer compositions. U.S. Patent Publication No. 2014/0179845 does not disclose or suggest the potential of manipulating plasticizer properties by changing the position of the ester group on the naphthalene ring or by varying the branching and length of the alcohol used to make the ester.

There is an increased interest in developing new plasticizers that offer alternatives to low molecular weight phthalates and which possess good plasticizer performance characteristics while remaining competitive economically. What is needed is a plasticizer with the correct balance of polarity or solubility and volatility and viscosity to have acceptable plasticizer compatibility with the resin. Plasticizers need also to exhibit good hydrolytic and thermal stability, low pour point, good aging performance and low temperature properties.

SUMMARY

In one aspect, the present application is directed to plasticizers comprising a compound selected from the group consisting of

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof.

In another aspect, the present application is directed to polymer compositions comprising a thermoplastic polymer and at least one plasticizer comprising a compound selected from the group consisting of

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, in which the thermoplastic polymer can be selected from the group consisting of vinyl chloride resins, polyesters, polyurethanes, ethylene-vinyl acetate copolymer, rubbers, poly(meth)acrylics and combinations thereof.

In yet another aspect, the present application is directed to a process for making a naphthoic acid ester plasticizer selected from the group consisting of

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, comprising the steps of: reacting naphthalene with carbon dioxide under conditions appropriate to form naphthoic acid; and reacting said acid group with a C4 to C15 linear or branched alcohol under esterification conditions to form naphthoic acid ester plasticizer. The plasticizer can subsequently be hydrogenated with hydrogen over a hydrogenation catalyst to form one or more saturated rings.

In still yet another aspect, the present application is directed to a process for making a naphthoic acid ester plasticizer selected from the group consisting of

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, comprising the steps of: methylating naphthalene under conditions appropriate to form methylnaphthalene; oxidizing methylnaphthalene under conditions appropriate to form naphthoic acid; and reacting said acid group with a C4 to C15 linear or branched alcohol under esterification conditions to form a naphthoic acid ester plasticizer. The plasticizer can subsequently be hydrogenated with hydrogen over a hydrogenation catalyst to form one or more saturated rings.

In still yet another further aspect, the present application is directed to a process for making a naphthoic acid ester plasticizer selected from the group consisting of

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, comprising the steps of: alkylating benzene or toluene with pentene or butene under conditions appropriate to form alkyl benzene or alkyl toluene; dehydrocyclizating alkyl benzene or alkyl toluene under conditions appropriate to form methylnaphthalene; oxidizing methylnaphthalene under conditions appropriate to form naphthoic acid; and reacting said acid group with a C4 to C15 linear or branched alcohol under esterification conditions to form a naphthoic acid ester plasticizer. The plasticizer can subsequently be hydrogenated with hydrogen over a hydrogenation catalyst to form one or more saturated rings.

In particularly preferred embodiments, the naphthoic acid ester plasticizers can be those wherein R is a hydrocarbon residue having an average carbon number (“ACN”) of C4 to C15 or an OXO-alcohol having a C4 to C15 alkyl chain, preferably a C7 to C15, C7 to C14, C9 to C14, C10 to C15, or C10 to C14 alkyl chain, such as nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, and isomers thereof. The OXO-alcohol may have a degree of branching averaging from 0.2 to 4.0 branches per residue or from 0.2 to 1.7, 1.8 to 3.8, 2.0 to 3.6, or 2.1 to 3.5 branches per residue. For purposes of this specification, the term “average carbon number” or ACN means the carbon number of a single molecule or the average of individual molecule carbon numbers in a group of molecules. The average carbon number (ACN) of the alcohols can be determined by ¹H NMR. ¹H NMR methods or ¹³C NMR methods can also be used to determine the degree of branching of the alcohol. According to the present invention, it is preferable to determine the degree of branching with the aid of ¹H NMR spectroscopy on a solution of esters in deuterochloroform (CDCl₃). The spectra are recorded, by way of example, by dissolving 20 mg of substance in 0.6 ml of CDCl₃, comprising 1% by weight of tetramethylsilane (TMS), and charging the solution to an NMR tube whose diameter is 5 mm. Both the substance to be studied and the CDCl₃ used can first be dried over a molecular sieve in order to exclude any errors in the values measured due to possible presence of water. The method of determination of the degree of branching is advantageous in comparison with other methods for the characterization of alcohol moieties, described by way of example in WO 03/029339, since water contamination in essence has no effect on the results measured and their evaluation. In principle, any commercially available NMR equipment can be used for the NMR-spectroscopic studies. The present NMR-spectroscopic studies used a Varian INOVA-500 spectrometer. The spectra were recorded at a temperature of 300 K using a delay of d1=10 seconds, 64 scans, a pulse length of 9.7 μs and a sweep width of 13 000 Hz, using a 5 mm BBO (broad band observer) probe head. The resonance signals are recorded in comparison with the chemical shifts of tetramethylsilane (TMS=0 ppm) as the internal standard. Comparable results may be obtained with other commercially available NMR equipment using the same operating parameters.

The degree of branching B can therefore be calculated from the measured intensity ratio in accordance with the following formula:

B=(2/3*I(CH₃)/I(OCH₂))−1

B is degree of branching, I(CH₃) is the area integral essentially attributed to the methyl hydrogen atoms, and I(OCH₂) is the area integral for the methylene hydrogen atoms adjacent to the oxygen atom.

The average carbon number (ACN) can therefore be calculated from the measured intensity ratio in accordance with the following formula:

ACN=I(CH₂,CH(OH)+I(CH₃)/I(OCH₂)

where ACN is the average carbon number, I(CH₃) is the area integral essentially attributed to the methyl hydrogen atoms, and I(OCH₂) is the area integral for the methylene hydrogen atoms adjacent to the oxygen atom.

Advantageously, in order to obtain optimum aging performance (e.g., sufficiently low plasticizer volatility), the average number of carbons in all hydrocarbon residues should be more than 9 carbons, such as for example 10, 11, 12, 13, 14 or 15 carbons.

The naphthoic acid ester plasticizer of the present disclosure when mixed and processed with PVC has been found to provide good plastisol rheology, good gelation and plasticizing efficiency.

In particularly preferred embodiments, the naphthoic acid ester plasticizer of the present disclosure can be represented by, but is not limited to, any of the following chemical structures:

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, such as linear or branched tridecyl-1-naphthoate or linear or branched tridecyl-2-naphthoate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an ¹H NMR spectrum of an inventive sample of dodecyl-2-napththoate.

FIG. 2 is a ¹³C NMR spectrum of an inventive sample of dodecyl-2-napththoate.

FIG. 3 is a graph of plastisol viscosity versus shear rate after one day for an inventive sample of dodecyl-2-napththoate.

FIG. 4 is a graph of elastic modulus (storage modulus) versus temperature (gelation curve) for an inventive sample of dodecyl-2-napththoate.

FIG. 5 is a graph of dry blending properties of certain inventive samples versus a DINP standard.

DETAILED DESCRIPTION

All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

There is an increased interest in developing new general purpose plasticizers that possess good compatibility with PVC while being cost competitive. The present disclosure is directed toward OXO-based ester plasticizers that can be made from low cost feeds and employ fewer manufacturing steps in order to meet economic targets.

Plasticizer and Polymer Compositions

It has been determined that plasticizers comprising one or more compounds selected from the group consisting of:

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof exhibit comparable performance to general purpose plasticizers for thermoplastic polymers, such as di-2-ethyl hexyl phthalate (DEHP), or di-isononyl phthalate (DINP) in flexible PVC. R may be a linear or branched alkyl group, including a C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, or C15 linear or branched alkyl group or combinations thereof. Particularly preferred linear alkyl groups are C7-C15, C9-C15, C7-C14, C9-C14, and C11-C15 linear alkyl groups, such as C11, C13, and/or C15 linear alkyl groups. Particularly preferred branched alkyl groups are C7-C15, C9-C15, C7-C14, C9-C14, and C11-C15 branched alkyl groups, such as C11, C13, and/or C15 branched alkyl groups.

The plasticizers of the present invention may have a dynamic viscosity measured according to ASTM D7042 of from 10 to 200 mPa·s, such as from 30 to 90 or 40 to 90 mPa·s. One can modify plasticizer neat properties and performance attributes in polymer compositions, such as gelation and fusion, volatility and aging performance, migration and extraction resistance, compatibility with PVC, low pour point and low temperature properties, and hydrolytic, chemical and thermal stability by varying the number of carbons in the alkyl chains R, the degree of branching of the alkyl chains R, and also the position of the ester functional group. It has been found that if the 20° C. kinematic viscosity or 20° C. cone-and-plate viscosity is higher than 250 mm²/sec, as measured by an appropriate ASTM test, it may affect the plasticizer process ability during formulation and require heating the plasticizer to ensure good transfer during storage and mixing of the polymer and the plasticizer.

The inventive plasticizers possess good performance characteristics and can be produced economically. They have a good balance of polarity/solubility and volatility/viscosity to have compatibility with various resins. They also exhibit hydrolytic and thermal stability, low pour point, good aging performance and low temperature properties.

In another embodiment of the invention, a polymer composition comprising a thermoplastic polymer and at least one plasticizer comprising at least one compound selected from the group consisting of

-   -   Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof provides particularly advantageous plasticizer performance properties. Non-limiting exemplary thermoplastic polymers include vinyl chloride resins, polyesters, polyurethanes, silylated polymers, polysulfides, acrylics, ethylene-vinyl acetate copolymer, rubbers, poly(meth)acrylics, and combinations thereof. Polyvinyl chloride (PVC) is a particularly preferred thermoplastic with the plasticizers of the present disclosure.

In certain embodiments of the invention, particularly preferred plasticizer compounds of the present disclosure include the following structures:

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol. Examples of commercially available alcohols that may be useful in making the inventive plasticizers include but are not limited to NEODOL 1, 91, 23, 25, and 135 available from Shell; isodecyl alcohol (EXXAL 10, available from ExxonMobil Chemical Company); and 2-propyl heptanol (available from BASF, Evonik and Perstorp).

Methods of Making Such Plasticizers

The naphthoic acid mono-ester plasticizers of the instant disclosure are formed by first forming naphthoic acid. The naphthoic acid is then esterified by reaction with a linear alcohol or a branched alcohol to form the naphthoic acid mono-ester plasticizers of the instant disclosure. The alcohol used is preferably an OXO-alcohol

One route to naphthoic acid mono-ester plasticizers of the present disclosure is by catalyzed oxidation of methyl naphthalene to form a naphthoic acid, as follows:

Subsequently, the naphthoic acid can be esterified by reaction with a linear or branched alcohol to form the naphthoic acid mono-esters of the present disclosure as shown below.

Another route to forming the naphthoic acid of the present disclosure is by direct carboxylation of naphthalene via carbon dioxide as shown below. Another route to naphthoic acid of the present disclosure is by direct methylation of naphthalene followed by oxidation as shown below and as also described above.

Subsequently, the naphthoic acid can be esterified by reaction with a linear or branched alcohol to form the naphthoic acid mono-esters of the present disclosure. The alcohol used is preferably an OXO-alcohol.

Yet another possible route for forming the naphthoic acid of the present disclosure is by using benzene or toluene as the starting material. The benzene or toluene is alkylated with pentene and/or butene followed by dehydrocyclization as shown below to form methylnaphthalene.

Subsequently, methylnaphthalene is oxidized under conditions appropriate to form naphthoic acid. The naphthoic acid is then esterified with a C4 to C15, preferably a C9 to C15, linear or branched alcohol under esterification conditions to form a naphthoic acid mono-ester. The mono-ester can subsequently be hydrogenated with hydrogen over a hydrogenation catalyst to form one or more saturated rings.

In more preferred embodiments, the naphthoic acids are esterified with OXO-alcohols, which are mixed linear and branched alcohol isomers, the formation of which is described in more detail below.

An “OXO-alcohol” is an organic alcohol, or mixtures of organic alcohols, which is prepared by hydroformylating an olefin, followed by hydrogenation to form the alcohols. Typically, the olefin is formed by light olefin oligomerization over heterogenous acid catalysts, which olefins are readily available from refinery processing operations. The reaction results in mixtures of longer-chain, branched olefins, which subsequently form longer chain, branched alcohols or acids, as described in U.S. Pat. No. 6,274,756, incorporated herein by reference in its entirety. The OXO-alcohols consist of multiple isomers of a given chain length due to the various isomeric olefins obtained in the oligomerization process, in tandem with the multiple isomeric possibilities of the hydroformylation step.

An “OXO-ester” is a compound having at least one functional ester moiety within its structure derived from esterification of either an acid or alcohol compound with an OXO-alcohol or OXO-acid, respectively.

“Hydroformylating” or “hydroformylation” is the process of reacting a compound having at least one carbon-carbon double bond (an olefin) in an atmosphere of carbon monoxide and hydrogen over a cobalt or rhodium catalyst, which results in addition of at least one aldehyde moiety to the underlying compound. U.S. Pat. No. 6,482,972, which is incorporated herein by reference in its entirety, describes the hydroformylation (OXO) process.

Branched aldehydes can be produced by hydroformylation of C3 to C15 olefins; in turn, some of these olefins have been produced by propylene and/or butene oligomerization over solid phosphoric acid or zeolite catalysts. The resulting C4 to C15 aldehydes can then be recovered from the crude hydroformylation product stream by fractionation to remove unreacted olefins. These C4 to C15 aldehydes can then hydrogenated to alcohols (OXO-alcohols). Single carbon number alcohols can be used in the esterification of the aromatic acids described above, or differing carbon numbers can be used to optimize product cost and performance requirements. The “OXO” technology provides cost advantaged alcohols and acids. Other options are considered, such as hydroformylation of C4-olefins to C5-aldehydes, followed by hydrogenation to C5-alcohols, or aldehyde dimerization followed by hydrogenation or oxidation to C10 alcohols. It is understood that the term “branched” describes the overall isomeric mixture of the aldehydes (and subsequent acids, alcohols, and R1 residues). Thus, a “branched” OXO-aldehyde, alcohol, or residue contains some portion of linear isomers mixed in with the individual branched isomers.

“Hydrogenating” or “hydrogenation” is addition of hydrogen (H2) to a double-bonded functional site of a molecule, such as in the present case the addition of hydrogen to the aldehyde to form the corresponding alcohol, and saturation of the double bonds in an aromatic ring. Conditions for hydrogenation of an aldehyde are well-known in the art and include, but are not limited to temperatures of 0-300° C., pressures of 1-500 atmospheres, and the presence of homogeneous or heterogeneous hydrogenation catalysts such as Pt/C, Pt/Al₂O₃ or Pd/Al₂O₃.

Alternatively, OXO-alcohols can be prepared by aldol condensation of shorter-chain aldehydes to form longer chain aldehydes, as described in U.S. Pat. No. 6,274,756, followed by oxidation or hydrogenation to form the OXO-acids or OXO-alcohols, respectively.

“Esterifying” or “esterification” is reaction of a carboxylic acid moiety, such as an anhydride, with an organic alcohol moiety to form an ester linkage. Esterification conditions are well-known in the art and include, but are not limited to, temperatures of 0-300° C., and the presence or absence of homogeneous or heterogeneous esterification catalysts such as Lewis or Brønsted acid catalysts.

As discussed above, the resulting OXO-alcohols can be used individually or together in mixtures having different chain lengths, or in isomeric mixtures of the same carbon chain length to make mixed esters for use as plasticizers. This mixing of carbon numbers and/or levels of branching can be advantageous to achieve the desired compatibility with PVC for the respective core alcohol used for the polar moiety end of the plasticizer, and to meet other plasticizer performance properties. The preferred OXO-alcohols are those having from 4 to 15 carbons, more preferably C11 to C15 alcohols, and even more preferably C11, C13, C15 alcohols, depending on the number of ester moieties and the desired volatility of the compound.

The overall isomeric distribution of OXO-alcohols may be described quantitatively by parameters such as average branch content per molecule or per chain position. Branching may be determined by Nuclear Magnetic Resonance (NMR) spectroscopy.

In one embodiment, preferred OXO-alcohols are those which result in R being a hydrocarbon residue of a C4 to C15, C7 to C15, or C11 to C15 OXO-alcohol averaging from 0.2 to 4.0, 0.2 to 1.7, 1.8 to 3.8, 2.0 to 3.6, or 2.1 to 3.5 branches per residue.

Typical branching characteristics of OXO-alcohols are provided in Table 1 below.

TABLE 1 ¹³C NMR Branching Characteristics of Typical OXO-Alcohols. Total Pendant Pendant OXO- Avg. % of α-Carbons β-Branches per Methyls per Methyls per Ethyls per Alcohol Carbon No. w/Branches^(a) Molecule^(b) Molecule^(c) Molecule^(d) Molecule C₄ ^(e) 4.0 0 0.35 1.35 0.35 0 C₅ ^(f) 5.0 0 0.30 1.35 0.35 0 C₆ — — — — — — C₇ 7.3 0 0.15 1.96 0.99   0.04 C₈ 8.6 0 0.09 3.0 1.5  — C₉ 9.66 0 0.09 3.4 — — C₁₀ 10.2 0 0.16 3.2 — — C₁₂ 12.2 0 — 4.8 — — C₁₃ 13.1 0 — 4.4 — — — Data not available. ^(a) COH carbon. ^(b)Branches at the-CCH₂OH carbon. ^(c)This value counts all methyl groups, including C₁ branches, chain end methyls, and methyl endgroups on C₂+ branches. ^(d)C₁ branches only. ^(e)Calculated values based on an assumed molar isomeric distribution of 65% n-butanol and 35% isobutanol (2-methylpentanol). ^(f)Calculated values based on an assumed molar isomeric distribution of 65% n-pentanol, 30% 2-ethylbutanol, and 5% 3-methylbutanol.

In general, for every polymer to be plasticized, a plasticizer is required with the correct balance of solubility, volatility, and viscosity to have acceptable compatibility with the resin. Volatility affects the long-term aging performance of flexible PVC. Higher volatility plasticizers can be lost by evaporation or diffuse out of the plastic material causing brittleness and article failure. The plasticizer neat volatility can be roughly predicted by the neat plasticizer weight loss at 220° C. using thermogravimetric analysis (see Tables 2 and 3). Neat plasticizer volatility can also be predicted by measuring the plasticizer weight loss at 24 hours at 155° C. according to ASTM D1048.

When C11 to C15 OXO-alcohols are used as reactants for the esterification reactions described above, the resulting OXO-esters are relatively high-boiling liquids (having volatility comparable to commercial plasticizers like DINP, DOTP, or Hexamol DINCH®), which are readily incorporated into polymer formulations as plasticizers (see Tables 2 and 3 below).

Polymer Compositions

The polymer composition comprising a thermoplastic polymer and at least one plasticizer blend described herein may optionally contain further additional plasticizers other than those produced herein, such as: dialkyl (ortho)phthalate, preferably having 4 to 13 carbon atoms in the alkyl chain; trialkyl trimellitates, preferably having 4 to 10 carbon atoms in the side chain; dialkyl adipates, having 4 to 13 carbon atoms; dialkyl sebacates preferably having 4 to 13 carbon atoms; dialkyl azelates preferably having 4 to 13 carbon atoms; preferably dialkyl terephthalates each preferably having 4 to 8 carbon atoms and more particularly 4 to 7 carbon atoms in the side chain; alkyl 1,2-cyclohexanedicarboxylates, alkyl 1,3-cyclohexanedicarboxylates and alkyl 1,4-cyclohexanedicarboxylates, and preferably here alkyl 1,2-cyclohexanedicarboxylates each preferably having 4 to 13 carbon atoms in the side chain; dibenzoic esters of glycols; mono benzoate esters with preferably an alkyl radical of 9 to 13 carbon atoms; alkylsulfonic esters of phenol with preferably one alkyl radical containing 8 to 22 carbon atoms; polymeric plasticizers (based on polyester in particular), glyceryl esters, acetylated glycerol esters, epoxy estolide fatty acid alkyl esters, citric triesters having a free OH group or are acetylated with for example alkyl radicals of 4 to 9 carbon atoms, alkylpyrrolidone derivatives having alkyl radicals of 4 to 18 carbon atoms and also alkyl benzoates, preferably having 7 to 13 carbon atoms in the alkyl chain. In all instances, the alkyl radicals can be linear or branched and the same or different.

Examples of commercially available benzenepolycarboxylic acid esters potentially useful herein as additional plasticizers to blend with the inventive plasticizers include phthalates such as PALATINOL AH (di-(2-ethylhexyl) phthalate; PALATINOL N (diisononyl phthalate); VESTINOL 9 (diisonyl phthalate); PALATINOL Z (diisodecyl phthalate); PALATINOL 10-P (di-(2-propylheptyl) phthalate); PALATINOL 711P (heptylundecyl phthalate); PALATINOL 911 (nonylundecyl phthalate); PALATINOL 11P-E (diundecyl phthalate); PALATINOL 11P-E; JAYFLEX DINP; JAYFLEX DIDP; JAYFLEX DIUP; JAYFLEX DTDP; and EMOLTENE 100. Examples of cyclohexane polycarboxylic acid esters useful herein include Hexamoll DINCHM (diisonyl cyclohexanoate); ELATUR CH (diisonyl cyclohexanoate); NanYa™ DPEH (bis(2-ethyl hexyl)cyclohexanoate); and NanYa™ DPIN (diisononyl cyclohexanoate). Examples of commercially available adipates useful herein include PLASTOMOLL DOA (diisononyl adipate); OXSOFT DOA; EASTMAN DOA (di-(2-ethylhexyl) adipates); and PLASTOMOLL DNA (diisononyl adipate). Examples of commercially available alkyl benzoates useful herein include: VESTINOL INB (isononyl benzoate); JAYFLEX MB10 (isodecyl benzoate); BENZOFLEX 131 (isodecyl benzoate); and UNIPLEX 131 (isodecyl benzoate). Particularly useful examples of plasticizers include the commercially available terephthalates such as Eastman 168TM; OXSOFT GPOTM; and LGFLEX GLTM 300 (bis(2-ethylhexyl) terephthalate). Particularly useful examples of plasticizers include the commercially available di-benzoate plasticizer mixtures such as: BENZOFLEX 988; BENZOFLEX 2088; KFLEX 500; and SANTICIZER 9000 series.

The polymer composition comprising a thermoplastic polymer and at least one plasticizer blend described herein prepared according to the present invention may further contain additives to optimize the chemical, mechanical or processing properties, said additives being more particularly selected from the group consisting of fillers, such as calcium carbonate, titanium dioxide or silica, pigments, thermal stabilizers, antioxidants, UV stabilizers, lubricating or slip agents, flame retardants, antistatic agents, biocides, impact modifiers, blowing agents, (polymeric) processing aids, viscosity depressants or regulators such as thickener and thinners, antifogging agents, optical brighteners, etc.

Thermal stabilizers useful herein include all customary polymer stabilizers, especially PVC stabilizers in solid or liquid form, examples are those based on Ca/Zn, Ba/Zn, Pb, Sn or on organic compounds (OBS), and also acid-binding phyllosilicates such as hydrotalcite. The polymer compositions to be used according to the present invention may have a thermal stabilizer content of 0.5 to 10, preferably 0.8 to 5 and more preferably 1.0 to 4 wt %, based upon the weight of the polymer composition.

It is likewise possible to use co-stabilizers with plasticizing effect in the polymer composition comprising a thermoplastic polymer and at least one plasticizer blend as described herein, in particular epoxidized vegetable oils, such as epoxidized linseed oil or epoxidized soya oil.

Antioxidants are also useful in the polymer composition comprising a thermoplastic polymer and at least one plasticizer blend described herein and can include sterically hindered amines—known as HALS stabilizers, sterically hindered phenols, such as TOPANOL CA, phosphites, UV absorbers, e.g., hydroxybenzophenones, hydroxyphenylbenzotriazoles and/or aromatic amines. Suitable antioxidants for use in the compositions of the present invention are also described for example in “Handbook of Vinyl Formulating” (editor: R. F. Grossman; J. Wiley & Sons; New Jersey (US) 2008). The level of antioxidants in the mixtures of the present invention is typically not more than 10 phr, preferably not more than 8 phr, more preferably not more than 6 phr and even more preferably between 0.01 and 5 phr (phr=parts per hundred parts of polymer composition).

Organic and inorganic pigments can be also used in the polymer composition comprising a thermoplastic polymer and at least one plasticizer blend as described herein. The level of pigments in the compositions to be used according to the present invention is typically not more than 10 phr, preferably in the range from 0.01 to 5 phr and more preferably in the range from 0.1 to 3 phr. Examples of useful inorganic pigments are TiO₂, CdS, CoO/Al₂O₃, Cr₂O₃. Examples of useful organic pigments are for example azo dyes, phthalocyanine pigments, dioxazine pigments and also aniline pigments.

The polymer composition comprising a thermoplastic polymer and at least one plasticizer blend described herein may contain one or more filler, including mineral and/or synthetic and/or natural, organic and/or inorganic materials, for example, calcium oxide, magnesium oxide, calcium carbonate, barium sulphate, silicon dioxide, phyllosilicate, carbon black, bitumen, wood (e.g. pulverized, as pellets, micropellets, fibers, etc.), paper, natural and/or synthetic fibers, glass, etc.

The compositions described herein can be produced in various ways. In general, however, the composition is produced by intensively mixing all components in a suitable mixing container at elevated temperatures. The plastic pellet or powder (typically suspension PVC, microsuspension PVC or emulsion PVC) is typically mixed mechanically, i.e., for example in fluid mixers, turbomixers, trough mixers or belt screw mixers with the plasticizer blend and the other components at temperatures in the range from 60° C. to 140° C., preferably in the range from 80° C. to 100° C. The components may be added simultaneously or, preferably, in succession (see also E. J. Wickson “Handbook of PVC Formulating”, John Wiley and Sons, 1993, pp. 747 ff). The polymer composition of PVC, plasticizer and other additive as described above (e.g., the PVC compound or the PVC paste) is subsequently sent to the appropriate thermoplastic molding processes for producing the finished or semi-finished article, optionally a pelletizing step is interposed.

The polymer compositions (e.g., the PVC compound or the PVC paste) are particularly useful for production of garden hoses, pipes, and medical tubing, floor coverings, flooring tiles, underbody car coating and sealants, latex and caulk, films, sheeting, roofing, or roofing webs, pool liners, building protection foils, upholstery, and cable filling compound, sheathing and wire insulation, particularly wire and cable coating, coated textiles and wall coverings.

The plasticizers of the invention are useful across the range of plasticized polyvinyl chloride materials. The plasticizers of the invention are useful in the production of semi-rigid polyvinyl chloride compositions which typically contain from 10 to 40 phr, preferably 15 to 35 phr, more preferably 20 to 30 phr of plasticizer (phr=parts per hundred parts PVC); flexible polyvinyl chloride compositions which typically contain from 40 to 60 phr, preferably 44 to 56 phr, more preferably from 48 to 52 phr plasticizer; and highly flexible compositions which typically contain from 70 to 110 phr, preferably 80 to 100 phr, more preferably 90 to 100 phr of plasticizer.

One widespread use of polyvinyl chloride is as a plastisol. A plastisol is a fluid or a paste consisting of a mixture of emulsion polyvinyl chloride and a plasticizer optionally containing various additives, such as those described above. A plastisol is used to produce one or more layers of polyvinyl chloride which are coated, pre-gelled, literally build-up and fused to produce coherent articles of flexible polyvinyl chloride. Plastisols are useful in the production of flooring, tents, tarpaulins, coated fabrics such as automobile upholstery, in car underbody coatings, in mouldings and other consumer products. Plastisols are also used in footwear, fabric coating, toys, vinyl glove, and wallpaper. Plastisols typically contain 40 to 200 phr, more typically 50 to 150 phr, more typically 70 to 120 phr, more typically 90 to 110 phr of plasticizer.

In a preferred embodiment of the invention, one or more (such as two or three) plasticizers produced herein are combined with a polymer such as PVC to form a PVC compound (typically made from suspension PVC) or a PVC paste (typically made from an emulsion PVC). A particularly useful PVC in the PVC compound or paste is one having a K value above 70. Particularly preferred PVC compounds or paste comprise: 20 to 150 phr (parts per hundred of resin) plasticizer(s), more preferably 30 to 70 phr and/or 0.5 to 15 phr stabilizer(s), and/or 1 to 30 phr, preferably 15 to 30 phr, filler(s), even more preferably the filler is calcium carbonate and the stabilizer is a calcium/zinc stabilizer. The above combination is useful in wire and cable coatings, particularly automobile wire and cable coating and or building wire insulation.

The following examples are meant to illustrate the present disclosure and inventive processes, and provide where appropriate, a comparison with other methods, including the products produced thereby. Numerous modifications and variations are possible and it is to be understood that within the scope of the appended claims, the disclosure can be practiced otherwise than as specifically described herein.

EXAMPLES

Several esters of 1- and 2-naphthoic acid were synthesized using the reaction scheme shown below and then compared with known commercial plasticizers including diisononyl phthalate (JAYFLEX DINP, PALATINOL N, VESTINOL 9), dioctyl terephthalate (DOTP, EASTMAN 168), and 1,2-cyclohexane dicarboxylic acid diisononyl ester (Hexamoll DINCH). In particular, the synthetic route for the preparation of material used for testing below was a one pot reaction starting from commercially available naphthoic acids with a titanium catalyst. In the route below, TIOT is titanium iso-octyl.

The naphthoic acid mono-ester plasticizers were then blended with PVC for plasticizer performance testing according the general procedure shown below. As shown in Table 2 below, compounds were blended with PVC and tested for volatility and viscosity. The dodecyl-2-naphthoate (Inventive Example 4) in this preliminary screening showed promising results compared to other general purpose plasticizers like DINP and DOTP.

General Procedure

A 4.5 g portion of the ester sample was weighed into an ERLENMEYER flask which had previously been rinsed with uninhibited tetrahydrofuran (THF) to remove dust. A 0.63 g portion of a 70:30 by weight solid mixture of powdered DRAPEX 6.8 (Crompton Corporation) and MARK 4716 (Chemtura USA Corporation) stabilizers were then added along with a stir bar. The solids were dissolved in 90 mL uninhibited THF. OXY VINYLS 240F PVC (9.0 g) was added in powdered form and the contents of the flask were stirred overnight at room temperature until dissolution of the PVC was complete (a PVC solution for preparation of an unplasticized comparative sample was prepared using an identical amount of stabilizer, 100 mL solvent, and 13.5 g PVC). The clear solution was poured evenly into a clean, flat aluminum paint can lid (previously rinsed with inhibitor-free THF to remove dust) of dimensions 7.5″ diameter and 0.5″ depth. The lid was placed into an oven at 60° C. for 2 hours with a moderate nitrogen purge. The pan was removed from the oven and allowed to cool for about 5 minutes. The resultant clear film was carefully peeled off the aluminum, flipped over, and placed back evenly into the pan. The pan was then placed in a vacuum oven at 70° C. overnight to remove any residual THF. The dry, flexible, almost colorless film was carefully peeled away again and exhibited no oiliness or inhomogeneity. The film was then cut into small pieces to be used for preparation of test bars by compression molding (size of pieces was similar to the hole dimensions of the mold plate). The film pieces were stacked into the holes of a multi-hole steel mold plate pre-heated to 170° C. and having hole dimensions 20 mm×12.8 mm×1.8 mm (ASTM D1693-95 dimensions). The mold plate was pressed in a PHI Company QL-433-6-M2 model hydraulic press equipped with separate heating and cooling platforms. The upper and lower press plates were covered in TEFLON-coated aluminum foil and the following multistage press procedure was used at 170° C. with no release between stages: (1) 3 minutes with 1-2 ton overpressure; (2) 1 minute at 10 tons; (3) 1 minute at 20 tons; (4) 1 minute at 30 tons; (5) 3 additional minutes at 30 tons; (6) release and 3 minutes in the cooling stage of the press (7° C.) at 30 tons. A knockout tool was then used to remove the sample bars with minimal flexion.

The data included herein show that effective aromatic plasticizers can be made from the methods disclosed herein.

Test procedures for measuring the performance properties of the plasticizers in Table 2 below were as follows:

1. Volatility was measured according to 98° C. weight loss comparison of PVC bars plasticized with esters versus PVC bars plasticized with a commercial plasticizer. More particularly, two each of the PVC sample bars were placed in aluminum weighing pans and placed inside a convection oven at 98° C. Initial weight measurements of the hot bars and measurements taken at specified time intervals were recorded and results were averaged between the bars.

2. Viscosity was measured versus shear rate and the value was taken at 334 ^(s−1).

As can be seen, the inventive naphthoic acid mono-ester examples in the tables above provide a good combination of volatility, and viscosity properties. In addition, four of the inventive naphthoic acid mono-ester examples (Inventive examples 1, 2, 4, and 7 in Table 2) provided particularly outstanding properties. All four provided a combination of outstanding volatility (less than or equal to 4.5 wt %) and viscosity. These four inventive naphthoic acid mono-ester plasticizers have a viscosity at 334 sec⁻¹ ranging from 33 to 57 centipoise. Comparative data for the commercial plasticizers JAYFLEX DINP (ExxonMobil Chemical Company), DOTP and Hexamoll DINCH (di-isonyl cyclohexanoate from BASF) is also included.

TABLE 2 Viscosity Vola- (cp @ Examples Description Structure tility 334s-1) Comparative Example 1 DINP

2.6 81 Comparative Example 2 DOTP

2.7 86 Comparative Example 3 DINCH

4 51 Comparative Example 4 Didecylnaphthalene- 1,8-dicarboxylate

0.4 75 Inventive Example 1 Decyl-2-naphtoate

3.9 50 Inventive Example 2 Decyl-1-naphtoate

4.5 33 Inventive Example 3 Decyl 5,6,7,8- tetrahydronapthalene- 2-dicarboxylate

4.2 45 Comparative Example 5 Dibutyl naphthalene 1,8-dicarboxylate

4.1 805 Comparative Example 6 Dibutyl naphthalene- 1,8-dicarboylate

1.8 473 Inventive Example 4 Dodecyl-2- naphthoate

2.5 57 Inventive Example 5 Exxal 10-2- naphthoate

5.2 84 Inventive Example 6 Exxal 13-2- naphthoate

3.0 197 Inventive Example 7 Dodecyl-1- naphthoate

2.3 41 Inventive Example 8 Exxal 13-1- naphthoate

3.5 106

Additional properties of the plasticizers are provided in Tables 3 and 4 below. Table 3 provides comparisons of volatilities (TGA weight loss %) and glass transition temperatures (Tg) of the different ester fractions. The Tg of the polymer compositions was determined using Dynamic Mechanical Thermal Analysis (“DMTA”). The Tg of the neat plasticizers was determined using Differential Scanning calorimetry (“DSC”). The Tg's given in Table 4 are midpoints of the second heats obtained by Differential Scanning calorimetry (DSC) using a TA Instruments Q2000 calorimeter fitted with a liquid N₂ cooling accessory. Samples about 10 mg in size were loaded at room temperature (about 22° C.), heated to 100° C. at 10° C./min, maintained at 100° C. for one minute, cooled to −90° C. at 10° C./min, maintained at −90° C. for one minute, and then reheated at 10° C./min. The Tg was recorded during the second heating. Thermogravimetric Analysis (TGA) was conducted on the neat esters using a TA Instruments TGA5000. Samples about 10 mg in size were loaded at room temperature (about 22° C.) and then heated at 10° C./min in an argon atmosphere, and weight loss was recorded at 220° C.

TABLE 3 1,2-naphtoate esters: neat properties TGA wt Viscosity/density loss % @ Tg/Pour pt @20° C. 220° C. (° C.) (mPa · s/g/cm3) Comparative DINP 3.2 (*) −80/−51 95/0.974 Example 1 Comparative DOTP 1.9 −36/−57 86/0.984 Example 2 Comparative DINCH 2.6 −90/−57 50/0.950 Example 3 Inventive Exxal 7-2- —   /−50  44/1.0276 Example 9 naphthoate Inventive Exxal 10-2- 8.4 −69/−43 93/1.007 Example 10 naphthoate Inventive Exxal 13-2-   /−38 190/0.9887 Example 11 naphthoate Inventive Exxal 10-1- 12.6  −74/−52 47/1.009 Example 12 naphthoate Inventive Exxal 13-1- 3.6 −67/−43 101/0.993  Example 13 naphthoate

The solution temperature of a plasticizer is the temperature at which a set amount of PVC gets dissolved in a set amount of plasticizer. The solution temperature is not only influenced by the plasticizer type but also by the PVC resin type and in particular the K-10 Value (DIN 53408 Testing of Plastics; Determination of Solubility Temperature of Polyvinyl Chloride (PVC) in Plasticizers (1967 Jun. 1)). A lower solution temperature indicates a plasticizer that will gel or fuse faster. The plasticizers of the present invention exhibit similar or substantially lower solution temperatures than DINP (Table 4).

Additionally, the plasticizers of the present invention made with branched alcohols exhibit very low pour points. Plasticizers based on linear alcohols tend to have high pour points, as shown in Inventive Example 15. Mixing linear and branched alcohol based naphthoates can lower the pour point of the resulting blend.

TABLE 4 C12-13 C13-15 2-naphthoate 2-naphthoate C10 C13 C10 C13 Inventive Inventive DINP 1-naphthoate 1-naphthoate 2-naphthoate 2-naphthoate Example 14 Example 15 Neat plasticizer 95 47 101 93 190 78 81 viscosity, mPa · s ASTM D7042 Solution 129 106 118 109 120 125 129 Temperature, ° C. DIN 53408 Pour Point, ° C. −51 −52 −43 −43 −38 −20 0 ASTM D5950

Flow properties of plastisols are important in spread coating processes like wall coverings, floorings, or coated fabrics. In general, low viscosity is desired at high shear rate. PVC plastisol formulations, prepared by mixing in a Hobart mixer, are provided in Table 5 below. The plastisols were prepared with 100 parts of PVC, 40 parts per hundred of PVC of plasticizer, and 2 parts per hundred of PVC of a conventional CaZn stabilizer. Formulation T52 contained DINP as a plasticizer for comparative purposes.

TABLE 5 Example T52 T53 T54 T55 T57 PVC 100 100 100 100 100 DINP 40 Isodecyl 2-naphthoate (Exxal 10) 40 (Inventive Example 10) Isodecyl 1-naphthoate (Exxal 10) 40 (Inventive Example 12) Isotridecyl 1-naphthoate (Exxal 13) 40 (Inventive Example 13) Isodecyl 2-naphthoate (Exxal 10) 40 (Inventive Example) Lankromark LZC525 2 2 2 2 2

The initial viscosity of the PVC plastisol formulations was evaluated at low shear by measuring the Brookfield viscosity after two hours at room temperature (about 22° C.) and 20 rpm. The plastisol viscosity stability was also evaluated by measuring the viscosity after one and two days. Results are shown in Table 6 below.

TABLE 6 Brookfield viscosity RT and 20 rpm mPa · s T52 T53 T54 T55 T57 2 hours 7700 7700 4150 11000 7600 1 day 5800 6900 4100 8000 8150 2 days 6900 9050 5300 9150 —

Plastisol formulations based on isodecyl-2-napthoate (T54) exhibit similar initial Brookfield viscosity to DINP-based plastisols, while plastisol formulations based on isodecyl-1-napthoate (T54) exhibit lower Brookfield viscosity than DINP-based plastisol formulations. Isodecyl-1-napthoate based plastisol formulations (T54) exhibit good viscosity stability over time. The viscosity of alkyl 1-naphthoate plastisol formulations (T55) increases with the alcohol carbon number.

An ¹H NMR spectrum of Inventive Sample 4, dodecyl-2-napththoate, is provided in FIG. 1. Additionally, a ¹³C NMR spectrum of Inventive Sample 4 is provided in FIG. 2.

Plastisols applied on a substrate (coating, dipping, gun-spraying) undergo a shear stress and exhibit shear thinning behavior. Plastisol viscosity under shear rate after one day storage at room temperature (about 22° C.) was assessed on several of the inventive examples and results are provided in FIG. 3, confirming the interesting rheology of the 1-naphthoate esters.

When processing plastisols, the gelling energy is worked only by heat-transfer. The higher the processing temperature needed, the longer the time needed to achieve plastisol gelation. Processors require plasticizers and plastisols with low processing temperature (faster gelling). The rate of plastisol storage modulus increase (G′ storage or elastic modulus) gives an indication of the plasticizer's fast gelling ability. Gelation behavior, from initial gelation and final gelation up to fusion, was obtained for the plastisol formulations and the gelation curve is provided in FIG. 4.

This gelation curve was obtained using dynamic mechanical analysis (DMA). Specifically, the curve was measured using an Anton Paar PHYSICA MCR 101 Rheometer equipped with the plate/plate measuring geometry. The settings were PP 50—frequency 1 Hz—amplitude 0.1%—heating rate 10° C./min—start temperature 20° C.—gap: 1 mm—end temperature 195° C., Normal force=0 Newton.

When gelation begins, both moduli (G′, G″) and complex viscosity (η*) rise sharply. The plasticizer begins to interact with the outer part of the PVC resin particles. When the gelation stage is completed, both moduli (G′, G″) and complex viscosity (η*) reach a maximum. The whole plasticizer has been absorbed by the PVC resin. When fusion takes place, the elastic and viscous moduli drop off and melting of the crystalline portion of the PVC occurs.

The gelation curves in FIG. 4 highlight the superior gelation performance of the plasticizers of the invention compared to DINP. The increased rate of the G′ (storage modulus) as a function of the temperature of the naphthoate based formulations occurs at a much lower temperature for the inventive formulations than for DINP. The maximum level achieved by the storage modulus is also much higher than DINP, indicating a higher elasticity maintained during initial and final gelation.

Table 7 provides three temperatures measured during the plastisol gelation process. Dynamic mechanical analysis of the inventive plastisol formulations as they were heated to final fusion gave initial and final gelation temperatures that are lower than the comparative example based on DINP. All tested naphthoate plasticizers were found to be faster fusing plasticizers with lower initial and final gelation temperatures.

TABLE 7 Plastisol gelation and figure storage modulus as a function of temperature. Temp. (° C.) T52 T53 T54 T55 Min gap 92 83 82 87 G′ at 10⁴ Pa 105 91 88 97 G′ at 10⁵ Pa 120 95 92 102

Mechanical properties of molded plastisols (hardness and Clash-Berg) were obtained. Pads were prepared from films obtained by curing plastisols in a Werner Mathis oven (setting 170° C./1 min @ 1500 rpm). Films were then pressed and molded at 180° C. for 15 min. Shore A and D hardness (ASTM D 2240-86) and cold flexibility performance were measured and are provided in Table 8. Naphthoate esters can offer a wide range of plasticizing efficiency, showing various Shore A or D hardness levels at the same plasticizer concentration. A C10 1-naphthoate is more efficient than DINP while a C13 based 1-naphthoate is less efficient. A C10 2-naphthoate exhibits similar plasticizing efficiency to DINP.

TABLE 8 Properties T52 T53 T54 T55 Shore A >90 >90 87 >90 Shore D 38 39 35 42 Clash-Berg T (° C.) −13 −4 −5 −7

Flexible PVC dumbbells made from the formulations shown in Table 9 were evaluated for their stiffness at low temperature. The formulations were prepared in a low speed Hobart mixer. The wet blend was processed into a flexible sheet by milling on a Dr. Collins roll mill at 165° C. for 6 minutes. The milled sheet was removed from the roll mill, cooled to room temperature, and then portions of this product were pressed to test specimens of various thicknesses at 170° C. for 15 minutes. After cooling, the test specimens were removed from the molds, and conditioned for 7 days at 22° C. and 50% relative humidity. The Shore A hardness (ASTM D 2240-86) and tensile properties (30 mil test specimens, Type C die)) were measured and are reported in Table 10 below. The naphthoate-based formulations were slightly stiffer than the DINP-based formulation. Additional properties of the formulations before and after aging are provided in Table 11.

TABLE 9 Example T1 T2 T3 T4 PVC (Solvin 271PC) 100 100 100 100 DINP 50 Isodecyl 2-naphthoate (Exxal 10) 50 Isodecyl 1-naphthoate (Exxal 10) 50 Isotridecyl 1-naphthoate (Exxal 13) 50 CaCO₃ 60 60 60 60 Baeropan 81/5 3 3 3 3

TABLE 10 T1 T2 T4 Shore A before aging 92 89 92 Shore D before aging 42 37 42 Shore A after aging 10 days @ 100° C. 91 89 91 Shore D after aging 10 days @ 100° C. 40 38 42

TABLE 11 Mechanical properties before and after aging 10 days @100° C. natural ventilation). T1 T2 T4 Before aging Force Mod-100% 13.1 12.2 13.6 Stress at Break (N/mm2) 18.7 19.6 19.6 Elongation at Break (%) 324 316 314 After aging Force Mod-100% 13.7 14.4 14.5 Stress at Break (N/mm2) 18.8 19.0 19.0 Elongation at Break (%) 315 280 298

The lower solution temperatures (higher solvency) of the inventive plasticizers translates into short dry blending time compared to DINP, as can be seen in Table 12 below and FIG. 5.

TABLE 12 T1 T2 T4 Dry Blending Time (s) 192 90 142 Solution temperature (° C.) 129 106 118

Additional information on the test methods used herein is provided below:

1) Brookfield Viscosity: ASTM D 1824—Standard test method is used for apparent viscosity of plastisols and organosols at low shear rates using a Brookfield viscometer, spindle RV 1 to 7.

2) Plasticizer Neat Viscosity and Density: ASTM D 7042—Standard Test Method is used for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity).

3) Low Temperature Flexibility: Clash-Berg measurement is used and based upon ASTM D 1043-84—Stiffness properties of plastics as a function of temperature by means of a torsion test.

4) Neat Plasticizer Volatility: Neat plasticizer weight loss (in wt %) is measured on neat plasticizer after heating plasticizer for 24 h at 115° C. in a forced ventilated oven (>160 air renewal/hour).

5) Solution Temperature: The solution temperature of plasticizers is defined as the temperature at which a set amount of PVC gets dissolved in a set amount of plasticizer. The solution temperature is not only influenced by the plasticizer type but also by the PVC resin type and in particular the K-10 Value (DIN 53408 Testing of Plastics; Determination of Solubility Temperature of Polyvinyl Chloride (PVC) in Plasticizers (1967 Jun. 1)).

6) Mechanical properties (original) were obtained from samples in a Zwick tensile tester measuring the modulus at 100% extension, the ultimate tensile strength in psi and ultimate elongation in % according to ASTM D 638. The same mechanical properties were measured on dumbbells that had been aged at 100° C. for 10 days, with airflow of +−150 air changes/hr.

7) Dry blending time was measured by using a planetary mixer P600 from Brabender. Planetary mixer are used for testing the plasticizer absorption rate of PVC powders or the pour ability of dry blends. A special rotor runs in a planetary motion in the mixer bowl while a revolving scrapper prevents the PVC mix from sticking to the mixer wall. PVC, CaCO3 and stabilizer are mixed first while heating the bowl to the set temperature. Plasticizer is than added after +−5 min. Torque and absorption time are recorded.

The meanings of terms used herein shall take their ordinary meaning in the art; reference shall be taken, in particular, to Handbook of Petroleum Refining Processes, Third Edition, Robert A. Meyers, Editor, McGraw-Hill (2004). In addition, all patents and patent applications, test procedures (such as ASTM methods), and other documents cited herein are fully incorporated by reference to the extent such disclosure is not inconsistent with this disclosure and for all jurisdictions in which such incorporation is permitted. Also, when numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.

The disclosure has been described above with reference to numerous embodiments and specific examples. Many variations will suggest themselves to those skilled in this art in light of the above detailed description. All such obvious variations are within the full intended scope of the appended claims. 

1. A plasticizer comprising a compound selected from the group consisting of

Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof.
 2. The plasticizer of claim 1, wherein R is a linear C9-C15 alkyl.
 3. The plasticizer of claim 1, wherein R is a C7 to C15 branched alkyl.
 4. The plasticizer of claim 1, wherein R is the hydrocarbon residue of a C7 to C15 OXO-alcohol averaging from 0.2 to 4.0 branches per residue.
 5. The plasticizer of claim 4, wherein the hydrocarbon residue averages from 1.8 to 3.8 branches per residue.
 6. The plasticizer of claim 5, wherein the hydrocarbon residue averages at least 1.3 to 3.0 methyl branches per residue.
 7. The plasticizer of claim 6, wherein the hydrocarbon residue averages from 1 to 2.5 pendant methyl branches per residue.
 8. The plasticizer of claim 1, wherein the viscosity at a shear rate of 334 sec.⁻¹ ranges from 20 to 80 centipoise.
 9. The plasticizer of claim 1, further comprising a second plasticizer comprising one or more of di-n-butyl terephthalate, diisobutyl terephthalate, di-n-octyl terephthalate, diisooctyl terephthalate, di-2-ethylhexyl terephthalate, di-n-nonyl terephthalate, diisononyl terephthalate, di-n-decyl terephthalate, di-2-propyl heptyl terephthalate, diisodecyl terephthalate, di-n-nonyl phthalate, diisononyl phthalate, di-n-decyl phthalate, diisodecyl phthalate, di-2-propyl heptyl phthalate, di-n-undecyl phthalate, ditridecyl phthalate, diisotridecyl phthalate, di-n-propyl isophthalate, di-n-nonyl isophthalate, diisononyl isophthalate, di-n-decyl isophthalate, diisodecyl isophthalate, di-2-propyl heptyl isophthalate, di-n-undecyl isophthalate, diisotridecyl isophthalate, isononyl benzoate, nonyl benzoate, isodecyl benzoate, decyl benzoate, 2-propylheptyl benzoate, isoundecyl benzoate, isotridecyl benzoate, di-heptyl cylohexanoate, di-2-ethylhexyl cylochexanoate, di-n-nonyl cylochexanoate, diisononyl cylochexanoate, di-n-decyl cylochexanoate, diisodecyl cylochexanoate, di-2-propyl heptyl cylochexanoate, diheptyl adipate, dioctyl adipate, diisononyl adipate, diisodecyl adipate, di 2-propylheptyl adipate, dipropylene glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol dibenzoate, or mixtures thereof.
 10. A polymer composition comprising a thermoplastic polymer and at least one plasticizer comprising a compound selected from the group consisting of

Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof.
 11. The polymer composition of claim 10, wherein the thermoplastic polymer is selected from the group consisting of vinyl chloride resins, polyesters, polyurethanes, ethylene-vinyl acetate copolymer, rubbers, poly(meth)acrylics and combinations thereof.
 12. The polymer composition of claim 11, wherein the thermoplastic polymer is polyvinyl chloride.
 13. The polymer composition of claim 12, wherein the thermoplastic polymer is a PVC suspension, a PVC microsuspension, a PVC emulsion, or a combination thereof.
 14. The polymer composition of claim 10, wherein R is a linear C9-15 alkyl.
 15. The polymer composition of claim 10, further comprising a second plasticizer comprising one or more of alkyl terephthalate, alkyl phthalate, a C7 to C13 alkyl benzoate ester, dibenzoate ester, an ester of cyclohexane polycarboxylic acid, and dialkyl adipate.
 16. The polymer composition of claim 10, wherein thermoplastic polymer is present at 99 to 40 wt % and plasticizer is present at 1 to 60 wt %, based on the total weight of the composition.
 17. The polymer composition of claim 10, wherein the composition comprises plasticizer in an amount of from 5 to 90 phr.
 18. The polymer composition of claim 10, further comprising at least one additive selected from the group consisting of trialkyl trimellite, alkylsulphonic ester, glycerol ester, isosorbide ester, citric ester, alkylpyrrolidone, and epoxidized oil.
 19. The polymer composition of claim 10, further comprising at least one additive selected from the group consisting of a filler, a pigment, a matting agent, a heat stabilizer, an antioxidant, a UV stabilizer, a flame retardant, a viscosity regulator, a solvent, a deaerating agent, an adhesion promoter, a process aid, and a lubricant.
 20. A process for making a naphthoic acid ester plasticizer selected from the group consisting of

Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, comprising the steps of: reacting naphthalene with carbon dioxide under conditions appropriate to form naphthoic acid; and reacting said acid group with a C4 to C15 linear or branched alcohol under esterification conditions to form a naphthoic acid ester plasticizer.
 21. The process of claim 20, wherein the C4 to C15 linear or branched alcohol is an OXO-alcohol.
 22. A process for making a naphthoic acid ester plasticizer selected from the group consisting of

Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, comprising the steps of: methylating naphthalene under conditions appropriate to form methylnaphthalene; oxidizing methylnaphthalene under conditions appropriate to form naphthoic acid; and reacting said acid group with a C4 to C15 linear or branched alcohol under esterification conditions to form a naphthoic acid ester plasticizer.
 23. The process of claim 22, wherein the C4 to C15 linear or branched alcohol is an OXO-alcohol.
 24. A process for making a naphthoic acid ester plasticizer selected from the group consisting of

Wherein R═C4 to C15 linear or branched alkyls

wherein R is a linear or branched alkyl residue of a C4 to C15 alcohol, and combinations thereof, comprising the steps of: alkylating benzene or toluene with pentene or butene under conditions appropriate to form alkyl benzene or alkyl toluene; dehydrocyclizating alkyl benzene or alkyl toluene under conditions appropriate to form methylnaphthalene; oxidizing methylnaphthalene under conditions appropriate to form naphthoic acid; and reacting said acid group with a C4 to C15 linear or branched alcohol under esterification conditions to form a naphthoic acid ester plasticizer.
 25. The process of claim 24, wherein the C4 to C15 linear or branched alcohol is an OXO-alcohol.
 26. The plasticizer of claim 1, wherein the plasticizer is used in a wire and cable coating formulation, cable filling compound, floor covering, wall covering, tarpaulin, coated textile, film, roofing sheet, banner, synthetic leather, packaging material, medical article, toy, seal, or automobile interior article. 